Rotary abrading tool



April 9, 1935. H. F. sKlLLlNGs 1,996,980

ROTARY ABRADING TOOL Filed Aug. 1e, 1935 lll/11111 Irweazn: Harold Patented Apr. 9, 1935 UNITED STATES PATENT OFFICE ROTARY ABRADING TOOL Harold F. Skillings, Arlington, Mass., assignor to The Blanchard Machine Company, Cambridge, Mass., a corporation of Massachusetts Application August 16, 1933, Serial No. 685,369

11 Claims.

other end of the Wheel is attached to a mounting ring. The invention will be understood by reference to the following description, when taken in connection with the accompanying drawing of one illustrative embodiment thereof, while its scope will be pointed out more particularly in the appended claims.

In the drawing:

Fig. 1 is a perspective View of a rotary, abrading tool embodying the invention;

2 is a side elevation of a portion of the tool;

Fig, 3 is a sectional view on line 3--3 of Fig. 2;

and

Fig. 4 is a sectional View on line 4-4 of Fig. 2. Referring to the drawing, and to the embodiment of the invention selected for illustration,

gether.

The Wheel is of the bonded, abrasive type, that is to say it is made up of grains of abrasive material bonded together by an appropriate bonding material, and each grain is like a small cutting tool. As the wheel is used, the grains break away gradually, and new cutting surfaces are presented to the work. Water is usually supplied to the interiory of the wheel to cool'theV latter, as well as the work, and to Wash away the cuttings and the abrasive grains which break oif. The wheel is usually mounted to rotate about avertical axis with the mounting ring upp the work is performed by the lower the wheel.

ermost, and end face of The wheel has an inner, continuous, annular wall 9 (see Fig, 3), coated as usual on itsr internal surface with a Waterproong material such as sulphur or parain, to prevent the water from percolating, and is provided with a circumferential series of notches I0, extending from the outer, circumferential surface of the wheel inwardly toward said wall, said notches being widened outwardly toward the outer, circumferential surface (see Fig. 4)

As shown, the notches extend from the working face il toward the mounting ring and terminate near the adjacent end or edge of the flange l of the mounting ring.

Thus the wheel has within the flange a continuous, annular, end wall l2. The wheel, as shown, is banded, as by several bands i3 of wire, each band comprising several turns of a wire I4, soldered at intervals, although it has been found in practice that without banding, the wheel has considerable strength, owing to the fact that it is in one piece.

The continuous, circumferential end wall l2 contributes to the strength of the wheel, as does also the increased radial thickness, which is greater than that of the usual cylinder wheel. Even without the banding and disregarding the strength of the inner, continuous wall, no section can tip outward about the edge of the mounting ring as a fulcrum, without the end of the section that is in the ring moving slightly inwardly, a motion that is strongly resisted by the fact that at that point, the sections merge into one continuous ring or arch l2, no portion of which can move inwardly without actually crushing the material.

The wheel allows chips to escape and Water to reach the working face and, as compared with a segment wheel, it has the advantage that the continuous, inner wall carries the water, which is supplied inside the wheel near the top, down to the face, so that no water can escape until it reaches the place where it is most needed, whereas in a segment wheel, the water can escape between the segments at the lower end of the segment chuck, without reaching the working` face of the wheel or the work.

Another advantage of the present wheel over segment wheels is that the continuous inner wall, in connection with ,the many small, integrally formed sections, minimizes or altogether eliminates the pounding and vibration common in segment wheels.

Still another advantage is that because the notches are on the outside, and especially as they enlarge toward the outer circumference, all chips and dirt are thrown clear of the wheel instead of accumulating and being held by the wheel as in some wheels heretofore used. y

It is desirable to make the notches enlarged outwardly for another reason, which constitutes an important advantage. With the notches shaped as shown, and considering concentric circles drawn on the wheel face about the axis, the linear distance occupied by abrasive at all circles is approximately the samer-that is to say, an outward widening of the notches makes the length that is occupied by abrasive along the outer circumference approximately equal to the 55 length occupied by abrasive on any other concen- -tric circle of smaller diameter.

This is advantageous because, owing to higher, linear speed, the outer portion of the face of a wheel tends to act harder and to hold its grains longer. By reducing the number of cutting grains along the outer circumference, the load on each grain is increased, and this compensates for the tendency of the outer portion of the wheel to act harder. However, the shape and size of the notches can be varied, they may be made wider or narrower than shown, the number may be varied, and they may be either angular or parallel sided, in order to secure a desired relation between the length of abrasive in contact with the work at various distances from the axis.

A further advantage over the usual solid cylinder wheel is that the notches allow chips to escape and water to readily reach the working face. This type of wheel cuts with less heating, and this cooler cutting permits the radial thickness to be increased,vthus increasing the volume of abrasive in each Wheel. This increases the life of the wheeL-that is, more work can be ground before the wheel requires replacement.

YStill another advantage flowing from the fact .that the notches are on the outside is that when the wheel is fed down by hand to engage the work to be ground, thenotches produce a siren-like sound which begins ordinarily when the wheel face is about .050 vabove the work. The volume of the sound increases as the space diminishes vand serves as an indication that the wheel face is about to engage the work, and at this point the power feed which compensates for wheel wear is engaged. This sound is not made by any other type wheel, in which case the wheel must be fed downwardly very slowly and carefully, because the wheel guard about the wheel cuts off the operators view of the Wheel face. Thus an audible indication is substituted for visual inspection in the preliminary setting of the wheel prior to the tarting of the automatic, wear-compensating eed. o

Having thus described one embodiment of the invention, but without limiting myself thereto, what I claim and desire by Letters Patent to secure is:

` l. Ina rotary abrading tool of the type in which a plane, end face of the tool does the abrading, the combination of a mounting ring, and an annular wheel, said wheel having a continuous, annular wall of bonded, abrasive material, and provided with a series of notches extending from the outer, circumferential surface inwardly toward `said wall, said notches extending from the working face of the wheel toward said ring and terminating short of the other end of said wheel.

2, In a rotary abrading tool of the type in which a plane, end face of the tool does the abrading, the combination of a mounting ring provided with an annular flange, and an annular wheel having one end mounted on said ring and having an outer, circiunferential surface encompassed by said flange, said wheel having a continuous, annular wall of bonded, abrasive material extending from end to end adjacent its inner, circumferential surface, said wheel being provided with a series of notches extending from its outer, circumferential surface inwardly toward said wall, said notches extending from the working face of said wheel toward said ring and terminating near the adjacent end of said flange.

3. A rotary abrading tool of the type in which a plane, end face of the tool does the abrading,

the same comprising a rigid wheel composed of grains of abrasive material which are bonded together and which break away in use, said wheel having an imperforate, continuous, annular wall yof bonded, abrasive material extending from end to end, said wheel being provided with a circumferential series of notches extending from the outer, circumferential surface inwardly toward said wall.

4. A rotary abrading tool of the type in which a plane, end. face of the tool does the abrading. the same comprising a wheel composed of grains of abrasive material bonded together, said wheel having an imperfcrate, continuous, annular wall of bonded, abrasive material extending from end to end, said wheel being provided with a circumferential series of notches extending from the outer, circumferential surface inwardly toward said wall, said notches extending from the working face of the wheel toward and terminating short of the other end face of the wheel.

5. A rotary abrading tool of the type in which a plane, end face of the tool does the abrading, the same comprising a rigid wheel composed of grains of abrasive material which are bonded together and which breakaway in use, said wheel having an imperforate, continuous, annular wall of bonded, abrasive material extending from end to end, said wheel being provided with a circumferential series of notches extending from the outer, circumferential surface inwardly toward said wall, said notches being widened outwardly toward said outer, circumferential surface.

6. A rotary abrading tool of the type in which a plane, end face of the tool does the abrading, the same `comprising a rigid wheel composed of grains of abrasive material which are bonded together and which breakaway in use, saidwheel having a continuous, circumferential, end wall for attachment to a mounting ring, the form of the wheel being such that on imaginary circles drawn from the axis of rotation as a center the linear distance occupied by abrasive vis approximately the same.

'7. A rotary abrading tool of the type in which a plane, end face of the tool does the abrading, the same comprising a rigid wheel composed of grains of abrasive material which are bonded together and which break away in use, said wheel having a continuous, circumferential, end wall for attachment to a mounting ring, said wheel being provided with a circumferential series of openings to its working face, of such form, number, dimensions and arrangement that on imaginary circles drawn from the axis of rotation as a center the linear distance occupied by abrasive is approximately the same.

8. A rotary abrading tool of the type in which a plane, end` face of the tool does the abrading, the same comprising a rigid wheel composed of grains of abrasive material which are bonded together and which break away in use, saidwheel having a continuous annular wall of bonded, abrasive material, said wheel being provided with a circumferential series of notches extending from the outer, circumferential surface inwardly toward said wall, the form, number, dimensions and arrangement of said notches being such that on imaginary circles drawn from the axis of rotation as a center the linear distance occupied by abrasive s approximately the same.

9. In an abrading tool of the type in which a plane, end face of the tool does the abrading, the combination of a mounting ring having an annular portion, and a rigid,.annular wheel composed of grains of abrasive material which are bonded together and which break away in use, said wheel having at one end a continuous, circumferential, end wall encompassed by said annular portion of said ring, the form of a remaining portion of said wheel being such that on imaginary circles dra-wn from the axis oi' rotation as a center, the linear distance occupied by abrasive is approximately the same.

10. In an abrading tool of the type in which a plane, end face of the tool does the abrading, the combination of a mounting ring having an annular portion, and a rigid, annular wheel composed 0f grains of abrasive material which are bonded together and which break away in use, said wheel having at one end a continuous, circumferential, end Wall encompassed by said annular portion of said ring, a remaining portion of said wheel being provided with a circumferential series of openings to its working face, of such form, number, dimensions and arrangement that on imaginary circles drawn from the axis of rotation as a center, the linear distance occupied by abrasive is approximately the same.

11. As a new article of manufacture, a rotary, rigid, annular wheel of the type in which a plane, end face of the tool does the abrading, the same being composed of grains of abrasive material which are bonded together and which break away in use, said wheel having at one end a continuous, circumferential, end wall for attachment to a mounting ring, said wheel having an inner, continuous, annular wall, and having about said inner Wall a discontinuous portion which is such that on imaginary circles drawn from the axis of rotation as a center the linear distanceoccupied by abrasive is approximately the same. y

' HAROLD F. SKILLINGS. 

